Why was this counted blunder?

I would say because if the black short castle you would have a sacrifice of the white bishop on H7, followed by queen check on H5.
I would say because if the black short castle you would have a sacrifice of the white bishop on H7, followed by queen check on H5.
But they might don’t castle?
I would say because if the black short castle you would have a sacrifice of the white bishop on H7, followed by queen check on H5.
But good point I guess

I would say because if the black short castle you would have a sacrifice of the white bishop on H7, followed by queen check on H5.
But good point I guess
On your game they castle right away after you move the knight, which was the logical move.
You ended up doing a check mat on the white diagonal with bishop/knight.
Just have a look at what would have happen if you had move the bishop and they had castled anyway and you followed with the bishop sacrifice and queen check.
Then you move the knight in F3 threatening G5 followed by mat with the queen. I had a look at this position and it seems to be pretty hard for black to defend.

One of the reason I did so many blunder yesterday is that last week I did only puzzle and Chessking app exercice.
On chessking it was "attaching the king protected by pawn" so I saw a lot of configuration where you had to sacrifice a piece to get access to the king.
That's really look like one of those "sacrifice a piece to gain access to the king and a decisive advantages".
I would say because if the black short castle you would have a sacrifice of the white bishop on H7, followed by queen check on H5.
But good point I guess
On your game they castle right away after you move the knight, which was the logical move.
You ended up doing a check mat on the white diagonal with bishop/knight.
Just have a look at what would have happen if you had move the bishop and they had castled anyway and you followed with the bishop sacrifice and queen check.
Then you move the knight in F3 threatening G5 followed by mat with the queen. I had a look at this position and it seems to be pretty hard for black to defend.
/On your game they castle right away after you move the knight, which was the logical move. /
actually when I checked the line of best move after Nf3, it was f6

And I was wrong.
I analysed the game with the chess.com engine and it consider it a blunder because you can have a better structure by moving a pawn before the knight.
And I was wrong.
I analysed the game with the chess.com engine and it consider it a blunder because you can have a better structure by moving a pawn before the knight.
Yes I checked the line. But is that really that much of a blunder? Maybe mistake could fit.
Is it because the position better or is there tactic?
I think it's cuz there's no where the knight can actually move now without getting taken... while the bishop has a couple options if you move it there. Also moving the knight to f3 blocks the queen from going out, if it has to be activated the next good spot would be d3 but if you had moved the bishop, you would've been able to bring queen to g4, attacking the g7 pawn and targeting the knight on d7. Then you probably could've moved bishop to f5 or vice versa... Idk fs tho.
Maybe this could be a reason

That's more the way the site characterize mistake, in the opening they are pretty big on the "have to move the pieces first".
End here moving the knight first prevent moving the pawn.
Keep in mind that it is just a chess engine.

The difference between the best move and your move just less than .30. So, I wouldn´t call it a blunder. Sometimes the classifications of the engine is not really reproducible. There is no taktik and you are still winning.
The difference between the best move and your move just less than .30. So, I wouldn´t call it a blunder. Sometimes the classifications of the engine is not really reproducible. There is no taktik and you are still winning.
Okay. I think the engine is angry that it wants me to save the move f4.

I would say because if the black short castle you would have a sacrifice of the white bishop on H7, followed by queen check on H5.
sacrifice doesnt work
When I look at it, it was looking very uncomfortable for black, so I tried to play it with the chess engine ( seriously I love the tool of this site).
I had miss the knight coming in F8, preventing check.
I would say because if the black short castle you would have a sacrifice of the white bishop on H7, followed by queen check on H5.
sacrifice doesnt work
When I look at it, it was looking very uncomfortable for black, so I tried to play it with the chess engine ( seriously I love the tool of this site).
I had miss the knight coming in F8, preventing check.
Check my diagram